From the not yet published PCT/EP86/00544, a device for controlling an automatic motor-vehicle clutch is known. With this device, an initial engagement speed which is well adjusted to the starting resistance becomes rapidly effective and it is possible to achieve not only a rapid but also a qualitatively good starting process by means of correction factors and influencing mechanisms.
In order to achieve the most economic fuel-consumption values, modern automatic transmissions have drive cycles with relatively low shift points, so that, in the case of a low engine rotation, vibrations can occur. While in an automatic transmission preceded by a hydrodynamic torque converter these vibrations cannot be passed, they are easily transmitted to the transmission in an automatic clutch-transmission combination, in spite of mechanically-acting dampers provided in such clutches against torsional vibrations.
As is known from FR-A 2 559 106 a device for the automatic adjustment of clutch attenuates torsional vibrations in the drive train through controlled changes in the clutch torque. However, the detection of these vibrations and defining the correction factors are complicated and expensive, requiring, besides considerable computing efforts and thus time consumption, as well as the consideration of characteristic values which have to be first determined and then fed into the memory. These characteristic values, for instance, the torsional rigidity in the respective gear, can vary between the respective drive trains, so that, in addition to the high cost, the read conditions in the drive train are not even fully considered. From JP-A-60/19 18 28, a device with a manually actuated clutch is known. Vibrations occurring in the drive train after the transmission are measured via a tacho-generator and are eliminated over a half-opened clutch. The clutch actuation for the half-opening takes place hereby via a control mechanism with a soleniud valve, which is superimposed on the manually driven actuation cylinder serving for the clutch actuation in order to eliminate the vibrations. Such a clutch-influencing mechanism can no longer be used in a modern drive train.
Further, from a control of a clutch travel according to German Open Application 3 531 434, it is known to adjust a clutch in such a way that a sliding torque transmittal by the clutch is equal or only slightly bigger than the torque transmitted after engine side. However this adjustment takes place in connection with rotation-speed differences before and after the clutch as a result of excessive loads.